Re: 26.1: calc-mode header line [PATCH]

[Eli Zaretskii <eliz@gnu.org>]

> Date: Mon, 31 Aug 2020 14:44:45 -0400
> From: Boruch Baum <boruch_baum@gmx.com>
> 
> Back in version 21, emacs introduced a static 'header-line' that could
> be inserted at the top of any buffer. Calc mode is one emacs package
> that does not use it and could benefit from it, so the attached patch
> offers that feature. The main benefit is that the 'calc trail' buffer
> (what some greybeards from the mechanical age would remember as the
> 'tape reel') no longer has its title line scroll off the visible
> window. The patch also includes:

Thanks, but it sounds like the change is backward-incompatible: the
old code which sets up the heading line is completely deleted, and if
calc-show-banner is nil, there's no heading line at all.

Can we please make this change backward-compatible, i.e. have a way
for users to get the previous behavior by setting calc-show-banner to
the nil value?  Or maybe make your changes conditioned by a new value
of calc-show-banner, different from nil and t?  Or maybe it's better
to introduce a new option?

In any case, there should be a NEWS item about the new behavior.
Bonus points for updating the Calc manual with the description of this
optional behavior.